Zigzag sewing machine for producing closed sewing patterns, particularly buttonholes

ABSTRACT

A zigzag sewing machine for producing closed sewing patterns composed of segments, such as buttonholes, includes regulating elements for the stitch width, field position, and length, and further includes retaining means for the stitch width and stitch field settings. A manually operable switch element controls the regulating elements through transmission means, such as levers, in accordance with the sewing course. The switching element is movable from an inoperative rest position into successive control positions each corresponding to a respective segment. Detent means releasably latch the switching element in each of its positions, and cams on the switching element control levers and the like in such manner that, when the switching element is moved from the inoperative position to the control position for sewing the initial segment of the pattern, all of the regulating elements which control the sewing pattern are moved into the starting position for sewing the closed sewing pattern. These regulating elements may be adjusted to their proper settings in advance of starting of the sewing operation.

PATENTEUJAMBIBH 3,635,179

MEET 1 OF 3 INVENTOR.

(BETTE UELTiClH BY y/Q 1 lava- PATENTEnJmlemz 3,635,179

sum 2 BF 3 INVENTOR.

ODE'ITE U ELTSC M MJJZ Tm FITTO'R NE Y5 PmEmEmwmz 3635 179 SHEET 3 [1F 3 INVENTOR.

ODE-1T8 UELTSC H! moneys ZIGZAG EIEWING MACHINE FOR PRODUCING CLOSED SEWING PATTERNS, PARTICULARLY EUTTONlilOLlES BACKGROUND OF THE INVENTION Known zigzag sewing machines for producing closed sewing patterns, such as buttonholes, having the disadvantage that the individual regulating elements for the stitch width, field position, length etc., must be set by hand, in certain starting positions, before the initiation, for example, of a buttonhole sewing operation. This setting operation must be repeated during the successive sewing of several buttonholes and before the initiation of the sewing for each new buttonhole. This repeated setting of the starting positions of the various regulating elements, required for sewing a pattern composed of segments, and measured by the duration of the sewing course, requires a great deal of time and frequently presents difficulties, particularly for unskilled operators, since a certain knowledge of the sewing machine is indispensible for setting the regulating elements.

SUMMARY OF THE INVENTION This invention relates to zigzag sewing machines for producing closed sewing patterns and, more particularly, to a novel and improved zigzag sewing machine of this type in which, when a series of identical closed sewing patterns are to be produced, it is not necessary to reset the stitch-regulating elements at the start of each successive closed sewing pattern.

With the zigzag sewing machine of the invention, the sewing of a closed pattern, particularly a buttonhole, can be started at any time without any preceding setting of the stitch-regulating elements. For this purpose, a zigzag sewing machine, embodying the invention, is so designed that, upon movement of the switching element or elements controlling the sewing course from an inoperative rest position into a control position corresponding to the pattern to be sewn, all the stitch-regulating elements influencing the sewing pattern are moved, irrespective of their respective settings, automatically into the starting position necessary for sewing the closed pattern. This is accomplished by providing the switching element with cams or the like which control, through transmission means, movement of the stitch-regulating elements into the starting position responsive to movement of the switching element to the first control position corresponding to the start of sewing of the closed pattern.

An object of the invention is to provide an improved and more simply operated zigzag sewing machine for producing closed sewing patterns.

Another object of the invention is to provide such a zigzag sewing machine in which the stitch-regulating elements, when once set. to the position corresponding to sewing of a closed pattern, are automatically moved into the starting position for the closed pattern responsive to movement of a switching element from an inoperative position to a control position corresponding to the start of the closed pattern.

A further object of the invention is to provide such a zigzag sewing machine in which the operation of sewing closed patterns is greatly simplified to the extent that such patterns can be sewn by a relatively unskilled operator.

For an understanding of the principles of the invention, reference is made to the following description of a typical em bodiment thereof as illustrated in the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS In the drawings:

FIG. 11 is a partial front elevation view of a zigzag sewing machine somewhat schematically illustrating the stitch-regulating elements and the regulating element for the closed sewing pattern;

FIG. 2 is an enlarged view, corresponding essentially to FIG. 1, with the front wall of the sewing machine removed and illustrating the control means, for the sewing of buttonholes, in their rest position;

FIG. 3 is a sectional view taken along the line A-B of FIG. 2 and illustrating the control means for the sewing of buttonholes and the stitch-setting device;

FIG. 4 is a front elevation view, partly in section, illustrating the retaining means for the stitch field setting and the stitch width setting in their operative position;

FIG. 5 is a view similar to FIG. 4 illustrating the retaining means in their inoperative position; and] r FIG. 6a-6f schematically illustrate the buttonhole control mechanism in the successive switching positions corresponding to the sewing course and in the rest position.

DESCRIPTION OF THE PREFERRED EMBODIMENTS Referring to FIG. l, a zigzag sewing machine embodying the invention is illustrated therein as including an arm 1, having an cover 2, and a baseplate 3. The sewing machine is driven by suitable driving means (not shown) through the medium of the hand wheel 4. The exposed portions of the stitch-regulating elements are visible on the forward vertical wall of arm I, and include an operating element 5, for regulating the stitch width, and having an indicating mark 116 cooperating, in a known manner, with a scale 6 representing the stitch width setting. The operating element 7, for setting the stitch field position, is arranged in the center of operating element 5 for the stitch width, and can be moved independently of element 5. A scale d indicates the stitch length as set by the operating element 9. A buttonhole is produced by moving switching element 10 to its various switch positions indicated at 11, each position 11 carrying a representation of the buttonhole segment produced when the element is adjusted to the particular representation 11. As illustrated, the indicating pointer or mark 50 of element 10 is at the 0 position, which may also be termed the inoperative rest position" of element 10.

FIGS. 2 and 3 illustrate, by way of example, the regulating elements for the stitch width, field position, and stitch length, as well as the switching element for the control of the buttonhole sewing, together with the necessary transmission or interconnection elements. Operating element 5, for setting the stitch width, is fixedly secured to a tubular shaft 12, rotatably mounted in sewing machine arm I, and carrying reversing lever 14 which is fixedly connected with hub 13. Hub 13 is fixedly connected, by screw 15, with tubular shaft 12, and secures shaft 12 against axial displacement. Arm R7 of reversing lever 14 carries a sliding block 18 which is guided in the jaw 19 of a guide fork 20.

Fork 20 carries a sliding block 21 guided along the regulating element 23 for the stitch width, and which is set into oscillation from arm shaft 22 by known means which have not been shown. Element 23 is operatively connected, by a known driving device which has not been illustrated, with the needle bar swing frame, which also has not been illustrated, but which is conventional. A braking spring 33, secured by means of screw 31 on a bearing member 32 of sewing machine arm 1, acts as a retaining member to keep the stitch width adjustment device in the set position.

A tension spring 54, connected at one end to reversing lever 14-, has its opposite end secured on a suspension bolt 55 fixed in the housing of arm 1, and pulls reversing lever 14, and thus arm 17, sliding book 11%, guide fork 20, and sliding block 21 into the zero position when braking a retaining spring 33 is inoperative. Sliding bock 21 is moved along regulating element 23, or the stitch width, under the influence of arm 17 which latter is connected with reversing lever M to block 18 and guide fork 20, and transmits the oscillating movement of regulating element 23 through a driving connection, which has not been shown, to the needle bar swing frame, which also has not been shown.

A shaft 24l telescoped in tubular shaft 12 is fixedly connected with operating element 7 for setting the stitch field position, and carries a locking lever 25 bearing on the inner end of tubular shaft 12, lever 25 being fixedly secured to shaft M by a screw 26. Locking lever 25 cooperates with a locking or setting retaining spring 27 secured on bearing block 32 by screw 34. Spring 27 serves to retain the set stitch field position, and locking lever or block 25 carries a bearing pin 29, for a connecting link 30, pin 29 being secured by means of a screw 28. In a known manner, connecting link 30 is connected with the zero point of regulating element 23 for the stitch width. To set the stitch field position, operating element 7 is turned in either direction, with locking lever 25 following the turning movement of element 7 and shifting, through link 30, the zero point, or effective oscillation axis, of regulating arm 23.

The regulating element 35, for setting the stitch length, is pivotally mounted, in a known manner, in sewing machine arm 1. A sliding block 37, mounted for movement in a slideway 36 of element 35, is rotatably mounted, by means of a setscrew 38, on stitch adjusting fork 39. Jaw 30 of fork 39 embraces an eccentric 41 secured on shaft 22 of sewing arm 1 A carrier 43 on regulating element 35 carries a hub 42 having a threaded bore into which a stitch adjusting bolt 46, fixedly connected with operating element 9, can be screwed and unscrewed.

A tension spring 47 is secured at one end on bolt carrier 43 and its opposite end is connected to a bolt 48 fixed in the housing, spring 47 biasing bolt carrier 43, and thus regulating element 35 and stitch-adjusting bolt 46 with its operating element 9, into the position for forward movement. The stitch length is regulated, by screwing or unscrewing adjusting bolt 46 connected with element 9, so that element 9 can be turned or swung, with regulating element 35, about the bearing point of the latter, to describe an are lying in a vertical plane. When the desired stitch length has been set, knob or operating element 9 is turned to screw bolt 46 into the hub 42 until knob 9 bears against the outer wall of sewing machine arm 1.

Control element for buttonhole sewing is fixedly connected with a shaft 49 rotatably mounted in sewing machine arm 1, and is provided with the marking 50 to indicate the particular segment of the buttonhole pattern being sewn. A discshaped switch element 51 is fixedly connected with shaft 49 by a screw 52. Element 51 preferably is formed of sintered material or of plastic composition material and has, on its outer end face, a first recessed cam groove 53 for controlling the stitch width regulating element 23 during the sewing of buttonholes. A feeler 56 of a feeler level 58, oscillatably mounted in a fixed bearing 57, is engaged in cam groove 53. The oscillatory movements of lever 58, as determined by cam groove 53, are transmitted to a carrier bolt 60 engaged in jaw 59 at the free end of lever 58, bolt 60 being fixedly connected to reversing lever 14 of the stitch width adjusting or setting means.

The rear end face of element 51 is formed with a cam groove 61 for controlling the stitch field position, and is engaged by a feeler 66 of a transmission lever 62 which is pivotally mounted on a collar stud 65 fixedly connected by a screw 63 with a stationary bearing block 64 of arm 1. Feeler 66 is pressed into cam groove 61 by a tension spring 68 secured at one end to lever 62 and at its other end to a fixed bolt 67. The movement resulting from the engagement of feeler 66 in cam groove 61 is transmitted to locking lever 25, for the stitch field position, by means of a carrier bolt 70 extending into the jaw 69 of lever 62 and secured to lever 25.

A cam plate 71, in the form of a chordally truncated circle, is provided on element 51 and serves to control the stitch density and the feeding direction during the sewing of buttonholes. Cam plate 71 is engaged by a feeler 73 of an operating lever 72 which is biased, in a cam plate engaging direction, by a tension spring 75 secured at one end to lever 72 and at its opposite end to a fixed bolt 74. Lever 72 is pivotally mounted on a fixed bolt 76, and has a free end 77 extending beneath the stitch length adjusting bolt 46, so that this bolt is moved, by lever 72 during its movement controlled by cam plate 71, into the positions necessary for sewing buttonholes.

The periphery of switching element 51 is formed with several locking notches corresponding to the various control positions of element 10 during the sewing of buttonholes, and these notches cooperate with a retaining spring 86 secured on machine arm 1 by a screw 85, in order to lock switching element 51 in the various switching positions.

In order to reduce the torque necessary for turning operating element 10 during sewing of buttonholes to as low a value as possible, a device is provided by means of which setting retaining springs 27 and 33 are made inoperative during sewing of buttonholes. A release lever 79 is pivotally mounted on a pivot or shaft 78 secured on bearing block 32, and has a downwardly extending arm 80 acting as a feeler to engage a peripheral cam surface 81 on switching element 51. When release lever 79 is turned counterclockwise about shaft 78, under the influence of cam 81, arm 82 of lever 79 moves toward setting retaining spring 33, as illustrated in FIG. 5, and pushes spring 33 away from reversing lever 14 to terminate the retaining effect of spring 33. Simultaneously, lever arm 33 pushes retaining spring 27 away from locking lever 25, and thus renders ineffective the retention of the stitch field position setting.

In the rest or inoperative position of switching element 51, as shown in FIGS. 1, 2, 4, and 6f, various regulating elements for the stitch width, stitch field position and stitch length can move freely when their respective operating elements 5, 7 and 9 are adjusted by the operator of the sewing machine, to set the desired stitch width, stitch field position and stitch length for buttonhole sewing.

The sewing operation with respect to a buttonhole is initiated with switching of element 10 from the position illustrated in FIG. 1 60 clockwise to the 2:00 oclock position as viewed in FIG. 1. With this adjustment of element 10, which is effect manually, switching element 51, fixedly secured with operating element 10, is moved into the position shown in FIG. 6a and retained therein by spring 86 engaging in the corresponding notch 84. Release lever 79 is turned counterclockwise about pivot shaft 78, at the start of the clockwise adjustment of operating element 10, under the influence of peripheral cam 81, so that its arm 82 presses against spring 33 and its arm 83 against spring 27. Thereby, both springs 33 and 27 are held in the inoperative position, illustrated in FIG. 5, during the entire buttonhole sewing operation. Reversing lever 14, which is no longer restrained against movement from its set position, is turned toward its start position by spring 54, and swings feeler lever 58 clockwise, or to the right, until feeler 56 bears on cam groove 53. Before switching element 51 has reached its first buttonhole sewing control position, reversing lever 14 is moved clockwise under the influence of cam 53 into a position which corresponds to a stitch width of about 1.8 mm.

The now freely movable locking lever 25 is turned about its fulcrum or pivot 87, such turning being effected by tension spring 68 operating on transmission lever 62 to turn lever 62 about its fulcrum 65, whereby jaw 69 engaged with bolt 70 thus swings locking lever 25. Such motion occurs until feeler 66 of lever 62 engages cam 61. The stitch field position is thus set to the left. Along with the stitch width and the stitch field position, the stitch length and the feeding direction also are set. Operating lever 72, with its feeler 73, is swung by tension spring 75 toward cam 71, and is turned counterclockwise about its fulcrum 76 by cam 71 acting on feeler 73. The free end 77 of lever 72, extending beneath stitch adjusting bolt 46, moves bolt 46 upwardly, against the bias of spring 47, and thus sets the regulating element 35, for the stitch length, so that a first bight seam can be sewn in a forward direction.

When the first bight seam has the desired length, operating element 10 is turned into its second buttonhole sewing control position, which is the 4:00 oclock position in FIG. 1, and switching element is turned into the position illustrated in FIG. 6b. The stitch width is set to 4 mm. under the influence of cam 53, and cam 61 steers the stitch field position to the right with cam 71 influencing the stitch length regulating element 35, through adjusting bolt 46, in such a way that a seam having a stitch length equal to that of the first bight seam can be sewn backward and, with this setting of the sewing machine, the first locking seam can be sewn.

To sew the second bight seam, operating element i is pushed into the third buttonhole sewing control position, which is the 6:00 o'clock position as illustrated in FIG. l, and switching element fill is turned into the position shown in FIG. 60. The stitch width is reset to 1.8 mm. under the influence of cam 53. The stitch field position remains set to the right, and the setting of the regulating element 35 for the stitch length remains unchanged.

When the second bight seam has reached the length of the first bight seam, operating element 10 is switched into the fourth buttonhole sewing control position, which is the 8:00 oclock position as illustrated in FIG. l. The position of the switching element is now as shown in FIG. 6d, and in which cam 53 has set the stitch width again to 4 mm. The stitch field position remains unchanged and set to the right. Operating lever 72 has swung clockwise, about its fulcrum 76, under the influence of cam 71 and tension spring 75. Stitch-adjusting bolt 46, and, with bolt 46, regulating element 35 is now again, under the influence of tension spring 47, in the position for forward stitching. The second locking seam is now sewn in the forward direction over the upper ends of the two bight seams.

A fifth sewing position, illustrated in FIG. he, is provided for securing the buttonhole. This is the 10:00 oclock position of element 10, as viewed in FIG. ll. In this fifth position of switching element 51, cam 53 has set the stitch width to zero through feeler lever d and reversing lever 14. The stitch field position, length, and feeding direction remain unchanged. In this fifth position, a few securing stitches are sewn, in a forward direction, on the right edge of the buttonhole.

After completion of the sewing of the buttonhole, operating element is moved into its zero position, which is the 12:00 oclock position illustrated in FIG. ll. At the start of rotation of element Sll from the fifth sewing position into its rest or inoperative position, locking lever is set in its center position under the influence of cam 61 and tension spring 68. When switching element Sll is turned further toward its inoperative position, release lever 79 returns to its rest position under the influence of cam 81, and releases retaining springs 33 and 27. Reversing lever I4 is now again held in its set position by retaining spring 33, and spring 27 again cooperates with locking lever 25 for retaining the set stitch field position.

Along with release lever 79, operating lever 72 leaves the range of movement of stitchadjusting bolt as and thus releases the stitch-adjusting device. Shortly before completion of the rotary movement of switching element 511 into its in operative position, feeler 66 of transmission lever 62 leaves the rang of influence of cam 61. The locking lever, for shifting the stitch field position, is thus set free and can be set as desired by adjustment of operating element 7.

The buttonhole sewing operation can be repeated as often as desired without making any change in the setting of the sewing machine, simply by stepwise shifting of operating element 10. After the sewing of a buttonhole is completed, the regular sewing can be carried out without any special measures being necessary.

Naturally, modifications can be made in the abovedescribed embodiment of the buttonhole sewing device. For example, instead of switching element 51 provided with cam grooves on its end faces for controlling the various regulating elements of the sewing machine, it is also possible to provide a switching element including several cam plates arranged in adjacent relation on the circumference of the switching element.

While a specific embodiment of the invention has been shown and described in detail to illustrate the application of the principles of the invention, it will be understood that the invention may be embodied otherwise without departing from such principles.

What is claimed is: i. In a zigzag sewing machine for producing closed sewing patterns, such as buttonholes, composed of segments, and including regulating elements for the stitch width, field osition and length, retaining means for the stitch width and stiiirh field settings, and a manually operable switching element controlling the regulating elements, through movable transmission means connected to the regulating elements, in accordance with the sewing course, the switching element being movable from an inoperative rest position into successive control positions each corresponding to a respective segment, the improvement comprising, in combination, cam means on said switching element operatively engageable with said transmission means, to move the same, and operable, responsive to movement of said switching element from said inoperative position to the control position for sewing the initial segment of the closed sewing pattern, to move said transmission means to move all of the regulating elements, controlling the sewing pattern, into the starting position for sewing the closed sewing pattern; said switching element comprising a single discshaped control body provided with earns cooperable with said transmission means; said control body having a plurality of locking notches on its periphery; a retaining spring cooperable with said notches to lock said switching element in its several positions; and additional cam on said control body; and con trol means engageable with said additional cam and controlling the operative position of said retaining means for the stitch width and stitch field settings; said control means cooperable with said additional cam moving said retaining means for the stitch width and stitch field settings into an inoperative position during the operation of producing said closed sewing pattern.

2. In a zigzag sewing machine for producing closed sewing patterns, the improvement claimed in claim I, in which said control body has a respective cam associated with each of the regulating elements for the stitch width, field position and length; said transmission means comprising respective transmission levers each cooperable with a respective cam and each rotating about a fixed fulcrum; respective setting elemerits controlling the regulating elements for the stitch width and stitch field position; the transmission levers for adjusting the stitch width and stitch field position being movably connected with the respective setting elements and effecting, during sewing of the closed pattern and under the influence of the associated cams, setting of the respective regulating elements; the regulating element for the stitch length including an adjusting device; the transmission lever for adjusting the stitch length being turned, under the influence of the associated cam, into the range of movement of said adjusting device to move the regulating element for the stitch length into the positions required for sewing of the closed sewing pattern; the cam contours being so designed that the transmission levers for the stitch width and field position can move freely, together with the respective setting elements therefor, in the inoperative rest position of said switching element; the transmission lever for adjustment of the stitch length being positioned outside the range of motion of said adjusting device in the inoperative rest position of said switching element; said switching element including a manual setting means, accessible from the exterior of the sewing machine, connected to said disc-shaped control body; all said transmission levers being moved into the range of action of the respective cams when said hand setting means is moved into the first control position for sewing the closed sewing pattern, to move the associated regulating element, through the respective setting elements, and independently of the respective positions of the regulating elements, into the positions required for sewing the first segment of the closed sewing pattern. 

1. In a zigzag sewing machine for producing closed sewing patterns, such as buttonholes, composed of segments, and including regulating elements for the stitch width, field position and length, retaining means for the stitch width and stitch field settings, and a manually operable switching element controlling the regulating elements, through movable transmission means connected to the regulating elements, in accordance with the sewing course, the switching element being movable from an inoperative rest position into successive control positions each corresponding to a respective segment, the improvement comprising, in combination, cam means on said switching element operatively engageable with said transmission means, to move the same, and operable, responsive to movement of said switching element from said inoperative position to the control position for sewing the initial segment of the closed sewing pattern, to move said transmission means to move all of the regulating elements, controlling the sewing pattern, into the starting position for sewing the closed sewing pattern; said switching element comprising a single disc-shaped control body provided with cams cooperable with said transmission means; said control body having a plurality of locking notches on its periphery; a retaining spring cooperable with said notches to lock said switching element in its several positions; and additional cam on said control body; and control means engageable with said additional cam and conTrolling the operative position of said retaining means for the stitch width and stitch field settings; said control means cooperable with said additional cam moving said retaining means for the stitch width and stitch field settings into an inoperative position during the operation of producing said closed sewing pattern.
 2. In a zigzag sewing machine for producing closed sewing patterns, the improvement claimed in claim 1, in which said control body has a respective cam associated with each of the regulating elements for the stitch width, field position and length; said transmission means comprising respective transmission levers each cooperable with a respective cam and each rotating about a fixed fulcrum; respective setting elements controlling the regulating elements for the stitch width and stitch field position; the transmission levers for adjusting the stitch width and stitch field position being movably connected with the respective setting elements and effecting, during sewing of the closed pattern and under the influence of the associated cams, setting of the respective regulating elements; the regulating element for the stitch length including an adjusting device; the transmission lever for adjusting the stitch length being turned, under the influence of the associated cam, into the range of movement of said adjusting device to move the regulating element for the stitch length into the positions required for sewing of the closed sewing pattern; the cam contours being so designed that the transmission levers for the stitch width and field position can move freely, together with the respective setting elements therefor, in the inoperative rest position of said switching element; the transmission lever for adjustment of the stitch length being positioned outside the range of motion of said adjusting device in the inoperative rest position of said switching element; said switching element including a manual setting means, accessible from the exterior of the sewing machine, connected to said disc-shaped control body; all said transmission levers being moved into the range of action of the respective cams when said hand setting means is moved into the first control position for sewing the closed sewing pattern, to move the associated regulating element, through the respective setting elements, and independently of the respective positions of the regulating elements, into the positions required for sewing the first segment of the closed sewing pattern. 